CBNA Rebirth Days

def graph(filename,f,a,b,n,delta=1e-2):
    print("Initialisation des variables.")
    vertice = [[0]*n for i in range(n)]
    dx = (b.real - a.real) / n
    dy = (b.imag - a.imag) / n
    sing = []
    print("Calcul des vertices.")
    for i in range(n):
        for j in range(n):
            try: vertice[i][j] = f(a + complex(i * dx,j * dy))
            except AssertionError: sing.append((i,j))
        print("  {} / {} colonnes traitées".format(i + 1,n))
    if sing != []:
        print("Gestion des {} points problématiques.".format(len(sing)))
        for (i,j) in sing:
            neighbor = []
            for x in range(i - 1,i + 2):
                if x >= 0 and x < n:
                    for y in range(j - 1,j + 2):
                        if y >= 0 and y < n and (x,y) != (i,j): neighbor.append((x,y))
            m,M = vertice[neighbor[0][0]][neighbor[0][1]],vertice[neighbor[0][0]][neighbor[0][1]]
            for (x,y) in neighbor[1:]:
                if vertice[x][y] < m: m = vertice[x][y]
                if vertice[x][y] > M: M = vertice[x][y]
            if M - m <= delta:
                S = 0
                for (x,y) in neighbor: S += vertice[x][y]
                vertice[i][j] = S / len(neighbor)
                sing.remove((i,j))
        print("  {} singularités restantes.".format(len(sing)))
    print("Ouverture du fichier.")
    file = open(filename,'w')
    print("Construction des vertices.")
    for i in range(n):
        for j in range(n):
            if (i,j) not in sing: file.write("v {} {} {}\n".format(i / n,j / n,vertice[i][j]))
            else: file.write("v -1 -1 -1\n")
    print("Construction des faces.")
    for i in range(n - 1):
        for j in range(n - 1):
            invalid = [[(i,j) in sing,(i + 1,j) in sing],[(i,j + 1) in sing,(i + 1,j + 1) in sing]]
            if invalid[0][0] or invalid[1][1]:
                if not (invalid[0][0] or invalid[0][1] or invalid[1][0]): file.write("f {} {} {}\n".format(n * i + j + 1,n * (i + 1) + j + 1,n * i + j + 2))
                if not (invalid[0][1] or invalid[1][0] or invalid[1][1]): file.write("f {} {} {}\n".format(n * (i + 1) + j + 1,n * (i + 1) + j + 2,n * i + j + 2))
            else:
                if not (invalid[0][0] or invalid[1][0] or invalid[1][1]): file.write("f {} {} {}\n".format(n * i + j + 1,n * (i + 1) + j + 2,n * i + j + 2))
                if not (invalid[0][0] or invalid[0][1] or invalid[1][1]): file.write("f {} {} {}\n".format(n * i + j + 1,n * (i + 1) + j + 1,n * (i + 1) + j + 2))
    print("Fermeture du fichier.")
    file.close()
    print("Fini. :DDDDD")